Characterization of the insertase for β-barrel proteins of the outer mitochondrial membrane.

The TOB-SAM complex is an essential component of the mitochondrial outer membrane that mediates the insertion of β-barrel precursor proteins into the membrane. We report here its isolation and determine its size, composition, and structural organization. The complex from Neurospora crassa was composed of Tob55-Sam50, Tob38-Sam35, and Tob37-Sam37 in a stoichiometry of 1:1:1 and had a molecular mass of 140 kD.

Self-assembly of colloidal particles into strings in a homogeneous external electric or magnetic field.

Colloidal particles with a dielectric constant (magnetic susceptibility) mismatch with the surrounding solvent acquire a dipole moment in a homogeneous external electric (magnetic) field. The resulting dipolar interactions can lead to aggregation of the particles into string-like clusters. Recently, several methods have been developed to make these structures permanent.

MSL2 combines sensor and effector functions in homeostatic control of the Drosophila dosage compensation machinery.

The process of dosage compensation (DC) in Drosophila counterbalances the monosomy of the X chromosome in male flies by increasing the transcription from this unique chromosome in the two-fold range. Upon exclusive expression of male-specific lethal 2 (MSL2) in males, the dosage compensation machinery assembles on active X-chromosomal genes. Overexpression of MSL proteins leads to aberrant binding of complex components to autosomes.

Df31 protein and snoRNAs maintain accessible higher-order structures of chromatin.

Packaging of DNA into nucleosomes and the formation of higher-order chromatin structures determine DNA accessibility and activity of genome domains. We identified an RNA-dependent mechanism maintaining the open chromatin structure within euchromatic regions in Drosophila cells. The mechanism of reversible chromatin opening, reconstituted in vitro, depends on the Drosophila decondensation factor 31 (Df31) that specifically binds to RNA and localizes to euchromatic regions.

Role of the AAA protease Yme1 in folding of proteins in the intermembrane space of mitochondria.

The vast majority of mitochondrial proteins are synthesized in the cytosol and transported into the organelle in a largely, if not completely, unfolded state. The proper function of mitochondria thus depends on folding of several hundreds of proteins in the various subcompartments of the organelle. Whereas folding of proteins in the mitochondrial matrix is supported by members of several chaperone families, very little is known about folding of proteins in the intermembrane space (IMS).

Fatal outcome after heart transplantation caused by Aspergillus lentulus.

Opportunistic invasive fungal infections are a major cause of mortality in immunocompromised patients. Early diagnosis of invasive aspergillosis and proper identification of the causative agent is crucial for guidance of therapy. Accurate differentiation of Aspergillus lentulus, a filamentous fungus often misidentified as atypical Aspergillus fumigatus, is of concern as multiple antifungal drugs show a reduced susceptibility.

DOT1A-dependent H3K76 methylation is required for replication regulation in Trypanosoma brucei.

Cell-cycle progression requires careful regulation to ensure accurate propagation of genetic material to the daughter cells. Although many cell-cycle regulators are evolutionarily conserved in the protozoan parasite Trypanosoma brucei, novel regulatory mechanisms seem to have evolved. Here, we analyse the function of the histone methyltransferase DOT1A during cell-cycle progression.

Colloidal analogues of charged and uncharged polymer chains with tunable stiffness.

Yanking the chain: a general method for the preparation of colloidal analogues of polymer chains was developed. The flexibility of these chains can be tuned by applying electric fields in combination with their subjection to simple linkage-forming procedures.

Secretome protein enrichment identifies physiological BACE1 protease substrates in neurons.

Cell surface proteolysis is essential for communication between cells and results in the shedding of membrane-protein ectodomains. However, physiological substrates of the contributing proteases are largely unknown. We developed the secretome protein enrichment with click sugars (SPECS) method, which allows proteome-wide identification of shedding substrates and secreted proteins from primary cells, even in the presence of serum proteins.

Myb-binding protein 1a (Mybbp1a) regulates levels and processing of pre-ribosomal RNA.

Ribosomal RNA gene transcription, co-transcriptional processing, and ribosome biogenesis are highly coordinated processes that are tightly regulated during cell growth. In this study we discovered that Mybbp1a is associated with both the RNA polymerase I complex and the ribosome biogenesis machinery. Using a reporter assay that uncouples transcription and RNA processing, we show that Mybbp1a represses rRNA gene transcription.

Clusterin in neurological disorders: molecular perspectives and clinical relevance.

Firstly discovered in rete testis fluid, clusterin is a glycoprotein present in most of the other biological fluids. Several isoforms of clusterin are encoded from a single gene located on chromosome 8 in human species. Among the different isoforms, the secreted form of clusterin is expressed by a variety of tissues, including the nervous system under normal conditions.

Synthesis of monodisperse, highly cross-linked, fluorescent PMMA particles by dispersion polymerization.

We describe a facile method to synthesize sterically stabilized monodisperse fluorescent poly(methyl methacrylate) (PMMA) colloids in the polar solvent mixture water/methanol with either a core-shell or a homogeneously cross-linked structure by dispersion polymerization. The particles were sterically stabilized by the polymer poly(vinylpyrrolidone) (PVP). The morphology of the particles was controlled by varying the moment at which the gradual addition of cross-linker and dye was started.

Directed orientation of asymmetric composite dumbbells by electric field induced assembly.

Assembly and directed orientation of anisotropic particles with an external ac electric field in a range from 1 kHz to 2 MHz were studied for asymmetric composite dumbbells incorporating a silica, titania, or titania/silica (titania:silica = 75:25 vol %) sphere. The asymmetric composite dumbbells, which were composed of a polymethylmethacrylate (PMMA)-coated sphere (core-shell part) and a polystyrene (PSt) lobe, were synthesized with a soap-free emulsion polymerization to prepare PMMA-coated inorganic spheres and another soap-free emulsion polymerization to form a polystyrene (PSt) lobe from the PMMA-coated inorganic spheres. The composite dumbbells dispersed in water were directly observed with optical microscopy.

Impairment of prostate cancer cell growth by a selective and reversible lysine-specific demethylase 1 inhibitor.

Post-translational modifications of histones by chromatin modifying enzymes regulate chromatin structure and gene expression. As deregulation of histone modifications contributes to cancer progression, inhibition of chromatin modifying enzymes such as histone demethylases is an attractive therapeutic strategy to impair cancer growth. Lysine-specific demethylase 1 (LSD1) removes mono- and dimethyl marks from lysine 4 or 9 of histone H3.

Connecting threads: epigenetics and metabolism.

Chromatin-modifying enzymes have long been proposed to be the authors of an epigenetic language, but the origin and meaning of the messages they write in chromatin are still mysterious. Recent studies suggesting that the effects of diet can be passed on epigenetically to offspring add weight to the idea that histones act as metabolic sensors, converting changes in metabolism into stable patterns of gene expression. The challenge will now be to understand how localized fluctuations in levels of metabolites control chromatin modifiers in space and time, translating a dynamic metabolic state into a histone map.

Probing the conformation of the ISWI ATPase domain with genetically encoded photoreactive crosslinkers and mass spectrometry.

We present a strategy for rapidly gaining structural information about a protein from crosslinks formed by genetically encoded unnatural amino acids. We applied it to ISWI, a chromatin remodeling enzyme involved in chromatin assembly, DNA replication and transcription. ISWI is part of the vast Snf2 family of helicase-related proteins, many of which constitute the catalytic cores of chromatin remodeling complexes.

Bonding assembled colloids without loss of colloidal stability.

A facile method is demonstrated for bonding assembled colloids without loss of colloidal stability by thermal annealing. Examples include both close-packed and non-close-packed structures. The confocal microscopy image shows a cross-section of a 3D labyrinthine structure after it was made permanent.

Developmental regulation of N-terminal H2B methylation in Drosophila melanogaster.

Histone post-translational modifications play an important role in regulating chromatin structure and gene expression in vivo. Extensive studies investigated the post-translational modifications of the core histones H3 and H4 or the linker histone H1. Much less is known on the regulation of H2A and H2B modifications.

Analgesic tolerance to high-efficacy agonists but not to morphine is diminished in phosphorylation-deficient S375A μ-opioid receptor knock-in mice.

Morphine is one of the most potent analgesic drugs. However, the utility of morphine in the management of chronic pain is limited by its rapid development of tolerance. Morphine exerts all of its pharmacological effects via the μ-opioid receptor.

Everolimus-eluting stents for treatment of chronic total coronary occlusions.

Background: After successful recanalization of a coronary chronic total occlusion (CTO) the risk for restenosis and subsequent need for repeat intervention is high. Everolimus-eluting stents (EESs) were associated with low rates of restenosis, reintervention and stent thrombosis in non-occluded lesions. We sought to determine the antiproliferative impact of the everolimus-eluting Xience V stent in CTOs.

Stage-specific histone modification profiles reveal global transitions in the Xenopus embryonic epigenome.

Vertebrate embryos are derived from a transitory pool of pluripotent cells. By the process of embryonic induction, these precursor cells are assigned to specific fates and differentiation programs. Histone post-translational modifications are thought to play a key role in the establishment and maintenance of stable gene expression patterns underlying these processes.

Post-infection immunocomplex glomerulonephritis and Legionnaires' disease in a patient with adult Still's disease during treatment with interleukin 1 receptor antagonist anakinra: a case report.

Introduction: Legionellosis is a systemic disease that primarily affects the lungs. However, dysfunction in many organ systems, including the kidneys, has also been described. There are only a few reported cases of renal dysfunction in patients with legionellosis.

Band formation in mixtures of oppositely charged colloids driven by an ac electric field.

We present experiments on pattern formation in a Brownian system of oppositely charged colloids driven by an ac electric field. Using confocal laser scanning microscopy we observe complete segregation of the two particle species into bands perpendicular to a field of sufficient strength when the frequency is in a well-defined range. Because of its Brownian nature the system spontaneously returns to the equilibrium mixture after the field is turned off.

Electrophoresis of concentrated colloidal dispersions in low-polar solvents.

We present a method to accurately measure the electrophoretic mobility of spherical colloids at high volume fractions in real space using confocal laser scanning microscopy (CLSM) and particle tracking. We show that for polymethylmethacrylate (PMMA) particles in a low-polar, density- and refractive-index-matched mixture of cyclohexylbromide and cis-decahydronaphthalene, the electrophoretic mobility decreases nonlinearly with increasing volume fraction. From the electrophoretic mobilities, we calculate the ζ-potential and the particle charge with and without correcting for volume fraction effects.

Potent anti-inflammatory and antinociceptive activity of the endothelin receptor antagonist bosentan in monoarthritic mice.

Introduction: Endothelins are involved in tissue inflammation, pain, edema and cell migration. Our genome-wide microarray analysis revealed that endothelin-1 (ET-1) and endothelin-2 (ET-2) showed a marked up-regulation in dorsal root ganglia during the acute phase of arthritis. We therefore examined the effects of endothelin receptor antagonists on the development of arthritis and inflammatory pain in monoarthritic mice.